Modern electronic devices, and particularly, integrated circuits, are at risk of damage due to electrostatic discharge (ESD) events. During an ESD event, a voltage (or current) may be provided to one or more terminals of an electronic device that causes the voltage between those terminals (or other terminals of the electronic device) to exceed the designed maximum voltage of the device, which could impair subsequent operation of the device. For example, a voltage at a terminal of an electronic device during an ESD event may exceed the breakdown voltage of one or more components of the device, and thereby potentially damage those components. Accordingly, electronic devices include discharge protection circuitry that provides protection from excessive voltages and/or currents across electrical components during ESD events.
To avoid interfering with normal operation of the device being protected, the discharge protection circuitry is typically designed to turn on and conduct current when the applied voltage exceeds the operating voltage of the device but before the applied voltage exceeds the breakdown voltage of the device. However, there is often a period of time between when the applied voltage exceeds the operating voltage of the device and when the applied voltage reaches the transient triggering voltage that fully turns on the discharge protection circuitry. During this time, the components of the device may be exposed to a portion of the discharge current, which, in turn, could undesirably impact the functionality of the components in the future. Existing approaches often involve tuning the breakdown voltages of the discharge protection circuitry to achieve the desired ESD performance; however, this often incurs area penalties or otherwise increases costs associated with the discharge protection circuitry.